A microphone is a type of transducer. It is used to convert acoustic energy (e.g., sound) into electrical signals. To enable a microphone to work efficiently, sound waves must be able to reach the microphone. In mobile computing devices that include a microphone, an opening or aperture in the housing is needed so that the microphone can register acoustic pressure.
However, having an opening or aperture in the housing of the mobile computing device may not be aesthetically pleasing. This can be more evident when a mobile computing device has more than one microphone so that multiple apertures may be needed.